Rope



Dec. 3, 1935.

s. A. REED 2,022,690

ROPE

Filed Dec. 21, 1934 2 Sheets-Sheet l J'iqam/Y/fed Dec; 3, 1935. s A, REED 2,022,690

ROPE

Filed Dec. 21, 1934 2 Sheets-Sheet 2 jrvewib r' fie/ieiz/f/i ea/ Patented Dec. v 3, 1935 ROBE Stephen A. Reed, Duxbury,'Mass., assignor to Pymouth Cordage Company, North Plymouth, Mass., a corporation of Massachusetts Application December 21, 1934, Serial No. 758,619 7 Claims (c1. 111-52) This invention relates to improvements in rope. Moreespecially it relates to rope made of hard fibre, of which manila, sisal and hemp, are examples; and it particularly provides an improved rope structure in which the strands may be formed and the rope laid with a pitch which is relatively long, as compared with customary practice, giving the increase of strength; and of flexibility, which naturally attend a long, loose pitch, but without that sacrifice of stability. which has heretofore attended a rope made with such a pitch.

Specifically it provides an improved means for prevention of intrusion and kinking of yarns when-the rope becomes back-twisted, in handling or in use.

In an ordinary standard construction the fibres .are first spun together in small groups each of which is called a yarn or thread. A multiplicity of these yarns are formedinto a. strand; and three or more strands may be laid together to make a rope. In a strand some of the yarns may be assembled in a core, and others assembled in one or more successive enclosing courses of covering yarns.

The successive twistings, of fibres into yarns, yarns into strands, and strands into rope, are ordinarily executed in successively opposite directions of twist. This makes a sort of balancing of the inherent untwisting tendencies of the various elements in the rope. A subsequent twisting of the completed rope in either direction tends to untwist parts of it and to twist other parts of it more tightly. Twist may be introduced caus-. ally by the coiling of a rope, or by the manner in which it is worked in, connection with a capstan, or by other circumstances. When this occurs-with suflicient severity the stresses and positions of yarns relative to each other within the rope become changed, and individual yarns or groups of yarns find relief by assuming loop, knub or kink formations and by intruding between other adjacent yarns. It is then difficult or impossible to restore the rope to proper form. The kinking therefore may mean the end of useful service of that section of rope and perhaps of the whole rope.

This is well understood in the cordage industry; and the preventative means commonly em-' ployed is to. make the twist initially tight. Such a rope has less kinking danger, but is much more difiicult to handle. Also the maximum tension it can bear without breaking is less, as can be seen by considering that the designing of a rope with 5 tighter twist means more turns per unit of length,

tribution of load on the yarns is not attained, and

and sets its yarns at a greater angle from parallelism with the axis.

The actual course of a yarn in a rope is a line compounded of helices, being always at some angle to the axis of the strand. Tension on the rope 5 results in a sort of shearing force, applied to every yarn, all along the rope. The greater the angle of the yarn to the axis of the strand, the greater is the shearing force, applied to it, and the less is that portion of its total strength which can 10 be resolved into and utilized as a force parallel to the axis. And the less the departure which the original formation, of a yarn in the strand, makes from approximate parallelism to the axis, the less is the shearing tendency when the load 15 is applied because the pull upon the yarn then occurs at less of an angle to the direction in which .the yarn itself extends.

The looser-or softer lay would obviously be more desirableffor many purposes, because it results in greater strength and greater flexibility, were it not for the danger'and losses of kinking, which, when it occurs, destroys the proper and necessary relations of rope elements, so that a proper disthere isresulting diminution of strength and durability of the rope, if not utter loss.

In United States Patent No. 1,660,065 granted onapplication of Ellis W. Brewster, there is shown an anti-kinking device in which a course of individually distinctive yarns is cross-wound over the core yarns, to prevent their becoming involved in a back-tum or strand kink. This aflords strong protection against back twisting, and this device serves its function so thoroughly that it may even prevent that change of twist which is incidental to a coiling of the rope; in which case there is the inconvenience that instead of being coiled the rope should be reeled.

In application for patent Serial No. 637,008, 0 pending in the names of Charles MacKinnon and Ellis W. Brewster, thereis disclosed an antikinking device in which a thin sheet element such as a sheet of paper is introduced as a septum. This has the disadvantage that the introduced paper is non-tensile in character, and adds to the weight and "cost without adding commensurately to the strength.

The present invention provides a non-kinking rope strand having improvements over these. The core structure may consist of yarns individually twisted according "to ordinary or standard practice, but, the strand is formed with these yarns assembled at the desired long pitch; and

thewhole rope" has a soft" lay. The security against the danger of kinks is assured without resort either to any cross-winding of yarns or to the introduction of non-tensile material such as paper which is-naturally foreign to a rope structure, for the anti-kinking element may be made wholly of the characteristic fibre of which the yarns and rope are made.

According to the present invention the proper The assurance of permanent separation of the core yarns from those in the cover courses being attained, the rope may be built with the softer lay; and'thereupon the greater strength, flexibility'and' durability of rope having a soft lay are attained. .The said unspun fibres, not individually secured togetherby twisting or otherwise, are wrapped helicaliy as a sheet intervening between the core yarns and the cover yarns. It is found that, whilethey are merely fibres which in general lie in a state -of mutual but not exact parallelism, they nevertheless, as

a body and within the thickness of, their sheet,

aided by the iribinding efiect of the course of cover yarns,have sufficient frictional or obstructional mutual interengagement to make it difficult for a body of similar material, such as a spun yarn, or a group of spun yarns, to force "its way between any of the individuals. Their casual v departures from strict parallelism, and the casual departure of any would-be penetrating yarn from parallelism therewith (even though both core yarns and septum fibres were formed at the same pitch), and the stout nature of. the individual. fibres themselves, are such that the penetration does not occur. But being formed around the core yarns, at an angle which may either be thesame as theirs or something 'difierent, they aiford and contribute tensile strength to the rope to whatever proportion of their total strength is provided by the angle at which they lie to the axis. The sheet of fibres thus described may be made on the drawing machines com-' monly employed in the preparation of fibres for spinning into yarns, the machine being adjusted so that its output is a silver having the requisite quantity or cross section of material for making a wrappedseptum of the desired thinness. The width of such a sliver will be made so that the required number of slivers, as may be designed, will smoothly cover the group of yarns which have passed through the tube of a strand forming machine, to constitute the core yarns of the strand, without spaces or overlapping in the coverage thus made bythe slivers as they pass onto the core yarns through suitable formed slots, nozzles or arcuate tubes that surround the core yarns in the forming machine. 'Or the slivers of unspun fibres may be braided as they are laid around the core yarns, making a tubular braided septum.

The interengagement of fibres laterally, sufficient for them to constitute the said barrier, is not an'eifect requiring to be introduced by any special step or separate process. Entanglement and promiscuous cross-positioning of fibres occurs incidentally during the preparation of fibres from natural'state to the state in which they are used for cordage. The combing and drawing operations of cordage manufacture have the pur- 5 pose of reducing their mutual cross-positioning; and it has been found that slivers of fibres as ordinarily combed for spinning into yarns have sufllcient non-parallelism to be suitable for making the septa; and indeed slivers which have not 10 been so far reduced toward parallelism can be The term "unspun as herein applied to fibres is' used, as in the trade, to signify not having been spun.

It is intended'that the patent shall cover, by suitable expression in the appended claims, what'- ever features of patentable novelty exist in the ginvention disclosed.

In the accompanying drawings: 20

Figure 1 is a diagrammatic side view of a fragment of three strand rope, inwhich the end of one strand is opened and the end of another broken away in sections, to reveal structural features of the invention, the second strand il- 25 lustrating a construction slightly different from the first? Figure 2 is a view in cross section of a strand embodying the invention but constructed'on still a different design; V 30 Figure 3 is similarly another modification;

Figure 4 illustrates, diagrammatically, parts of mechanism for forming the strand, the sliver condensing cone having portions broken away to show its divided interior construction; i

Figure 5 is an elevation showing a braided form of unspun fibre septum; and

Figure 6 is a perspective showing a fragment of a flattened sliverwherein a slight twist was made before the flattening. 40

Referring to the drawings, the rope ofFigure l, having the three strands ill, 12 and I4, serves to represent a rope of any number or lay. of strands. For conciseness two slightly different constructions are represented in strands Ill and '45 I 2; but in practice all three strands of a three. strand rope will ordinarily be alike in content,' in design and in lay. I

As here represented the strand. lil comprises core yarns l6 and covering yarns i8, both the 50 "core and the cover being formed with a twist whose pitch may be longer than would be considered practicable in ordinary/rope heretofore regarded as standard. The longer pitch-is called I "softer, although really the compactness, den- 56 sity and tension of the elements may be no less. This greater approximation of each yarn to parallelis'm with the axis lets each tensile yarn contribute more nearly its full strength to the loadcarrying ability of the rope as a whole, before 60 breakage of that yarnfpccurs, andlets it wear longer at lower tension, the reason being thatthe resultant shearing stress on each yarn is less. The core of spun yarns it may be formed in the usual way, either by rotating their supply o5 spools or the finished strand, preferably passing the yarns through a tube which condenses and compacts them, and being covered a little further along by 'the course l8, of'spun yarns, in the usual way, But, according to the invention, 7 a thin covering sheet 20 made of. combed slivers of unspun fibres is laid around the corelyarns It, so as to intervene in the strand betweenthe core yarns and the cover yarns: J

Figure 4 portrays somewhat diagrammatically apparatus which may be employed in forming the improved strand, and one manner of associating the fibre elements together. The spun fibre core yarns l6 are twisted together in passing through tube 24, whence the twisted yarn core extends axially through the conical condenser 26 by means of which the septum of unspun fibre is laid around the core. The condenser 26 has an axial hole 28 for free passage of the core, and has'three of the partitions 30 dividing its interior into three passageways 3|, each of which diminishes in breadth and thickness toward the small end of the cone, and each terminating in a thin slot 33 interiorly of the neck of the conical condenser, so that a sliver 29 of fibre entering the condenseras a mass more or less round in cross-section is compressed and thinned into a sheet-form in the'course of its travel to one of the narrow slot outlets.

continuous, thin sheet-like septum hereinbefore described.

Beyond the condenser, the outer course of spun j yarns l8 may be formed in a usual manner, ex- 25 cept that its yarns will have the mentioned longer pitch than is usual. All parts of the strand I may have the same pitch.

In the strand in of Figure 1, the core and cover yarns I6, L8 have pitch and direction approximately the same, and the intervening sheet 20 of unspun fibres, similar in pitch and direction,

covers the inner yarns Hi to a uniform depth. The laying of the strands themselves in the 0pposite direction makes theneeded balance. By

having all yarn elements of the strand, and also the sheet of unspun fibres, laid in the same direction and with approximately the same pitch,

great flexibility of strand is attained; and a mini-' mum of rubbing and shearing stresses are imposed -by fibres or yarns on adjacent elements. But whether or not thepitch be alike for all, the yarn elements can contribute to the strand respectively more nearly their full individual strength, because of the longer pitch; the barrier sheet or septum of unspun fibres prevents kinking and thus makes the rope safe in case of back twisting; and whatever strength lies in these unspun fibres is also contributed.

However, this equality of pitch and direction is not essential, and advantages may be obtained when the cover yarns I 8 are formed at a different pitch and/or in a different direction with respect 'to the core yarns l6. Also the sheath of unspun fibre 20 may be arranged with its direction ex.- tending across the lay of either core or cover yarns, or both.

The body of unspun fibre 2t or 2| may be only a thin sheet, since its reason for existence is only to hold elements of one group from becoming in- ,truded among the yarns of another group. It

constitutes an insulator for maintaining a segregated relation as between core and cover elements. In this sheet the more or less inter-engaged status of many fibres collaterally with their neighbors prevents yarns from breaking through the sheet of unspun fibres. The said lateral entanglement is but slight, and in some senses of the word,

especially as applied to the relation between one particular fibre and another particular fibre, would ordinarily not be recognized as an entanglement. But the fibres may be a layer several fibres deep, having a thickness of a small fraction of an inch. In the sliver each is inherently only approximately rectilinear and parallel to the. stream, so that when formed around the core The condensed slivers are laid around the core to provide the each fibre lies in non-strict conformity to exact helicality. Some parts of it usually lie between adjoining fibres on one or the other side making a mild mat formation; and this has been found sufficient in a strand to prevent the passage through it of a body as big as a spun yarn, under the circumstances in which the mat is held by being enclosed between cover yarns and core of spun yarns, the invention can also be applied a to a core made up otherwise, including fibres associated in unspun form, or composite of spun and unspun fibre.

If desired each of the groups of'unspun fibres, which together make the complete septum, may be slightly twisted before the group is flattened to the form shown in Figure 4; and this slight twist would then be present in the group when flattened, as shown in Figure 6.

Figure 5 shows a barrier septum wherein the unspun fibres arranged in a plurality of ribbons 29 are braided to form the septum intervening between the interior yarns I6 and the exterior yarns I8.

I claim as my invention:

1. In a rope strand having a multiplicity of spun yarns of vegetable fibres arranged as an interior group, and a multiplicity of spun yarns of vegetable fibres arranged in a group surrounding the said interior group, the combination therewith of a multiplicity of unspun fibres contiguously associated together and intervening as a septum between the said interior and surrounding groups and constituting a barrier to kinking of the strand by the moving of an element from one said group into the region of elements of the other said group.

2. In a rope strandhaving a multiplicity of spun yarns of vegetable fibres arranged as an interior group, and a multiplicity of spun yarns of vegetable fibres arranged in a group surrounding the said interior group, the combination therewith of a multiplicity of unspun fibres contiguously associated together and intervening as a septum between the said interior and surrounding groups; the said septum having individual fibres deviating promiscuously, relative to their associated contiguous fibres of the same prevailing trend, whereby a mat is constituted of fibres in the septum barring the passing of .a ,yarn from one said group into the region of the other said group.

3. In a rope strand having a multiplicity of spunvegetable fibre yarns arranged inan interior group, and a multiplicity :of spun vegetable fibre yarns arranged in a group surrounding the interior group, the combination therewith of a multiplicity of u'nspun fibres introduced in' ribbon form and intervening between the said groups; said ribbon formation being positioned and thereby organized as a barrier in the strand, for limiting displacement of said interior yarns into the region of said surrounding yarns.

4. In a rope strand having a multiplicity or spun vegetable fibre yarns arranged in an interior group, and a multiplicity of spun vegetable fibre yarns arranged in a group surround- I ing the interior group, the combination therewith of a multiplicity of unspun fibres introduced in ribbon form and intervening between the said groups; said unspun fibres being flexible tensile elements of the strand with a prevalent longitudinal trend therein, laid around said interior group and thereby organized for limiting displacement of said interior yarns into the region of said surrounding yarns, and for contributing to the tensile strength of the rope strand.

5. In a rope strand,amulticplicityof spun yarns of vegetable fibres arranged in an interior group, and a multiplicity of spun yarns of vegetable fibre arranged in an exterior group, surrounding the interior group, combined with unspun fibres compacted into sheet form and laid as a septum intervening between said interior and exterior groups of yarns; said fibres in the septum having a prevalent longitudinal trend combined with a lateral trend and with minor deviations of individual fibres, whereby some overlap others 25 laterally.

' 6. In a rope strand having a multiplicity of spun yarns or vegetable fibres arranged as an interior group, and a multiplicity of spun yarns of vegetable fibres arranged in a group surrounding the interior group, the combinationtherewith o! a multiplicity of unspun fibres compacted in a sheet in mutual relations of approximate parallelism, as between contiguous fibres, and with promiscuous minor deviations from said parallelism these said unspun fibres intervening as a septum between the said groups.

10 7. In a rope strand having a multiplicity of spun yarns of vegetable fibres arranged as an interior group, and a multiplicity of spun yarns of vegetable fibres arranged in a. group surrounding the interior group, the combination therewith oi a multiplicity of unspun fibres contiguously associated together and intervening as a septum between the said interior and surrounding groups and constituting a barrier to kinking of the strand by the moving of an element from Q one said group into the region of elements of the other said group; said unspun fibres being assembled together in ribbons a plurality of which are braided to from the said barrier septum.

STEPHEN A. REED. 

